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521.
Molecular genetics has revealed a precise stereotypy in the projection of primary olfactory sensory neurons onto secondary neurons. A major challenge is to understand how this mapping translates into odor responses in these second-order neurons. We investigated this question in Drosophila using whole-cell recordings in vivo. We observe that monomolecular odors generally elicit responses in large ensembles of antennal lobe neurons. Comparison of odor-evoked activity from afferents and postsynaptic neurons in the same glomerulus revealed that second-order neurons display broader tuning and more complex responses than their primary afferents. This indicates a major transformation of odor representations, implicating lateral interactions within the antennal lobe. 相似文献
522.
Nieto P Pijper E Barredo D Laurent G Olsen RA Baerends EJ Kroes GJ Farías D 《Science (New York, N.Y.)》2006,312(5770):86-89
The Born-Oppenheimer approximation of uncoupled electronic and nuclear motion is a standard tool of the computational chemist. However, its validity for molecule-metal surface reactions, which are important to heterogeneous catalysis, has been questioned because of the possibility of electron-hole pair excitations. We have performed experiments and calculations on the scattering of molecular hydrogen from a catalytically relevant metal surface, obtaining absolute probabilities for changes in the molecule's velocity parallel to the representative Pt(111) surface. The comparison for in-plane and out-of-plane scattering and results for dissociative chemisorption in the same system show that for hydrogen-metal systems, reaction and diffractive scattering can be accurately described using the Born-Oppenheimer approximation. 相似文献
523.
Chollet M Guerin L Uchida N Fukaya S Shimoda H Ishikawa T Matsuda K Hasegawa T Ota A Yamochi H Saito G Tazaki R Adachi S Koshihara SY 《Science (New York, N.Y.)》2005,307(5706):86-89
We report that the organic salt (EDO-TTF)2PF6 with 3/4-filled-band (1/4-filled in terms of holes), which forms an organic metal with strong electron and lattice correlation, shows a highly sensitive response to photoexcitation. An ultrafast, photoinduced phase transition from the insulator phase to the metal phase can be induced with very weak excitation intensity at near room temperature. This response makes the material attractive for applications in switching devices with room-temperature operation. The observed photo-induced spectroscopic change shows that this photoinduced phase transition process is caused by the cooperative melting of charge ordering assisted by coherent phonon generation. 相似文献
524.
PRACTICAL RELEVANCE: Feline trauma is commonly seen in general practice and frequently involves damage to the head. CLINICAL CHALLENGES: While craniofacial injuries following trauma vary widely in severity, affected cats can often be severely compromised in terms of their neurological, respiratory and cardiovascular status, and their management can be challenging in both the short and long term. They need prompt stabilisation and careful monitoring in the initial period to maximise prospects of a successful outcome. Many cats with severe facial trauma will require surgery to stabilise skull fractures or address injuries to the eyes, with its inherent issues surrounding pain management, ensuring adequate nutrition and the necessity for ongoing hospitalisation. DIAGNOSTICS: Cats with head trauma benefit from imaging of the injured areas as well as thoracic radiography. Imaging the skull can be challenging and is best performed under general anaesthesia. In unstable patients this can be delayed to prevent any associated morbidity. EVIDENCE BASE: The clinical evidence base relating to injury to the feline head is limited, despite its relative frequency in general practice. This review focuses on the initial approach to craniofacial (in particular, ocular and jaw) trauma, and outlines simple techniques for management of soft tissue and bone injuries. Much of the information is based on the authors' clinical experience, as there is a paucity of well-described clinical case material. 相似文献